ON THE DYNAMICS OF THE SPIN-1 2 ISING-MODEL IN A TRANSVERSE FIELD/

A new solution for the spin-1/2 Ising model in an external transverse field for the case of three-dimensional nearest-neighbor interactions is obtained. The chain of equations for high-order Green functions is decoupled in the scope of symmetrized Tyablikov's scheme and consisten tly reduced to a closed equation system, which is solved exactly. This improves previous relevant solutions by short-range quantum correlati on effects caused by spins involved in small compact clusters and sugg ests a new dynamic description of the paramagnetic phase of ferroelect rics, to which the model is directly applied.